New 'Shoes' for the
Space Shuttle Transporter
(11 July 2005) Help is usually
just a phone call away when the family car has a flat tire. But what's a rocket
scientist to do when new "shoes" are needed for the massive "crawlers" that
transport the space shuttle to the launch pad?
That is
exactly the situation NASA faced last year as it worked toward the shuttle
program's return to flight. Potentially dangerous cracks were discovered in the
huge metal treads that carry the two massive transporters along a rocky, 3-mile
path from Cape Canaveral's Vehicle Assembly Building to the launch pad.
A Minnesota foundry was scheduled to forge replacements for the damaged
treads. But the on-time shuttle launch was threatened by a global shortage of a
seemingly simple, but critical material - sand.
"This isn't just any
sand," explains Rechea Hutchinson of United Space Alliance (USA), the prime
contractor of the NASA shuttle fleet. "It's zircon, the only kind of sand that
can be used in this type of high-temperature casting process."
USA
tried to purchase the special zircon sands in Australia and South Africa, but
the material was not available.
"And then we discovered that DuPont
had a mining operation in Florida - right in our backyard," says Hutchinson.
"We asked for their help."
The primary product of the DuPont mine,
near Starke, is ore used to make titanium dioxide, a white pigment used in
paper, paints and plastics. Zircon and other minerals are mined along with the
titanium ore. At the DuPont site, a huge dredge called "The Sandpiper" pumps
more than 30 thousand gallons of water and sand every minute. Only two percent
of the dredged sand actually contains precious titanium ore and the
accompanying zircon.
NASA's urgent request for 225 tons of zircon sand
to forge the treads was assigned a top priority by the DuPont Florida plant. In
fact, DuPont delivered enough zircon sand to the foundry to complete tread shoe
production for both crawlers in December, along with spares to support NASA for
the next 100 years.
As an added benefit, the unique particle shape of
the DuPont zircon sand used in the tread casting process reduced vibration and
noise on the transporter, making the shuttle's trip to the launch pad
safer.
United Space Alliance and NASA recognised DuPont's efforts at a
March supplier recognition event. "We're proud that DuPont could play a role in
helping support the shuttle program's return to flight," said Florida Plant
Manager Ken Klein. "DuPont science has always supported America's space
program."
DuPont is a science company. Founded in 1802, DuPont puts
science to work by creating sustainable solutions essential to a better, safer,
healthier life for people everywhere. Operating in more than 70 countries,
DuPont offers a wide range of innovative products and services for markets
including agriculture, nutrition, electronics, communications, safety and
protection, home and construction, transportation and apparel.
(source: DuPont)